/*-
 * Copyright (c) 2014,2016 Microsoft Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/reboot.h>
#include <sys/systm.h>

#include <dev/hyperv/include/hyperv.h>
#include <dev/hyperv/include/vmbus.h>
#include <dev/hyperv/utilities/vmbus_icreg.h>
#include <dev/hyperv/utilities/vmbus_icvar.h>

#define VMBUS_SHUTDOWN_FWVER_MAJOR      3
#define VMBUS_SHUTDOWN_FWVER            \
        VMBUS_IC_VERSION(VMBUS_SHUTDOWN_FWVER_MAJOR, 0)

#define VMBUS_SHUTDOWN_MSGVER_MAJOR     3
#define VMBUS_SHUTDOWN_MSGVER           \
        VMBUS_IC_VERSION(VMBUS_SHUTDOWN_MSGVER_MAJOR, 0)

static int                      vmbus_shutdown_probe(device_t);
static int                      vmbus_shutdown_attach(device_t);

static const struct vmbus_ic_desc vmbus_shutdown_descs[] = {
        {
                .ic_guid = { .hv_guid = {
                    0x31, 0x60, 0x0b, 0x0e, 0x13, 0x52, 0x34, 0x49,
                    0x81, 0x8b, 0x38, 0xd9, 0x0c, 0xed, 0x39, 0xdb } },
                .ic_desc = "Hyper-V Shutdown"
        },
        VMBUS_IC_DESC_END
};

static device_method_t vmbus_shutdown_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         vmbus_shutdown_probe),
        DEVMETHOD(device_attach,        vmbus_shutdown_attach),
        DEVMETHOD(device_detach,        vmbus_ic_detach),
        DEVMETHOD_END
};

static driver_t vmbus_shutdown_driver = {
        "hvshutdown",
        vmbus_shutdown_methods,
        sizeof(struct vmbus_ic_softc)
};

DRIVER_MODULE(hv_shutdown, vmbus, vmbus_shutdown_driver, NULL, NULL);
MODULE_VERSION(hv_shutdown, 1);
MODULE_DEPEND(hv_shutdown, vmbus, 1, 1, 1);

static void
vmbus_shutdown_cb(struct vmbus_channel *chan, void *xsc)
{
        struct vmbus_ic_softc *sc = xsc;
        struct vmbus_icmsg_hdr *hdr;
        struct vmbus_icmsg_shutdown *msg;
        int dlen, error, do_shutdown = 0;
        uint64_t xactid;
        void *data;

        /*
         * Receive request.
         */
        data = sc->ic_buf;
        dlen = sc->ic_buflen;
        error = vmbus_chan_recv(chan, data, &dlen, &xactid);
        KASSERT(error != ENOBUFS, ("icbuf is not large enough"));
        if (error)
                return;

        if (dlen < sizeof(*hdr)) {
                device_printf(sc->ic_dev, "invalid data len %d\n", dlen);
                return;
        }
        hdr = data;

        /*
         * Update request, which will be echoed back as response.
         */
        switch (hdr->ic_type) {
        case VMBUS_ICMSG_TYPE_NEGOTIATE:
                error = vmbus_ic_negomsg(sc, data, &dlen,
                    VMBUS_SHUTDOWN_FWVER, VMBUS_SHUTDOWN_MSGVER);
                if (error)
                        return;
                break;

        case VMBUS_ICMSG_TYPE_SHUTDOWN:
                if (dlen < VMBUS_ICMSG_SHUTDOWN_SIZE_MIN) {
                        device_printf(sc->ic_dev, "invalid shutdown len %d\n",
                            dlen);
                        return;
                }
                msg = data;

                /* XXX ic_flags definition? */
                if (msg->ic_haltflags == 0 || msg->ic_haltflags == 1) {
                        device_printf(sc->ic_dev, "shutdown requested\n");
                        hdr->ic_status = VMBUS_ICMSG_STATUS_OK;
                        do_shutdown = 1;
                } else {
                        device_printf(sc->ic_dev, "unknown shutdown flags "
                            "0x%08x\n", msg->ic_haltflags);
                        hdr->ic_status = VMBUS_ICMSG_STATUS_FAIL;
                }
                break;

        default:
                device_printf(sc->ic_dev, "got 0x%08x icmsg\n", hdr->ic_type);
                break;
        }

        /*
         * Send response by echoing the request back.
         */
        vmbus_ic_sendresp(sc, chan, data, dlen, xactid);

        if (do_shutdown)
                shutdown_nice(RB_POWEROFF);
}

static int
vmbus_shutdown_probe(device_t dev)
{

        return (vmbus_ic_probe(dev, vmbus_shutdown_descs));
}

static int
vmbus_shutdown_attach(device_t dev)
{

        return (vmbus_ic_attach(dev, vmbus_shutdown_cb));
}